<template lang="">
    <div class="count">
        <h2>当前求和为:{{sum}}</h2>
        <select v-model.number="n">
            <option value="1">1</option>
            <option value="2">2</option>
            <option value="3">3</option>
        </select>
        <button @click="add">加</button>
        <button @click="down">减</button>
    </div>
</template>

<script lang="ts" setup>
import { ref } from 'vue'
let sum = ref(1)
let n = ref(1)   //用户选择的数字
function add() {
 sum.value +=n.value

}
function down() {
 sum.value -=n.value

}
</script>
<style scoped>

    .count {
        background-color: pink;
        padding: 10px;
        border-radius: 0 0 10px;
        box-shadow: 0 0 10px
    }
    select,button {
        margin: 0 5px;
        height: 50px;
    }
</style>